When you press them for a reason why they want labeling, it's inevitably winds up being "because I want it" or "other countries already do it". When there are exactly zero people who have died or even sickened by anything that is directly attributable to GMO after decades of use, there simply is no rational argument for it.

If you really want to hear the sound of crickets, just mention mutation breeding. If the anti-GMO crowd were genuinely afraid of GMO, they would be scared shitless of mutation breeding, yet surprisingly (or unsurprisingly) there's zero effort to label it. Some products produced by mutation breeding are even labeled organic because they are fully eligible to be certified under the NOP, while GMO is not. Very telling that. When you find out about things like that you realize the "organic" label is really nothing more than a marketing term which is now fully under the control of moneyed interests and the effort to label GMO is really nothing more than the attempt at using the power of government to grab market share for those moneyed interests. Science, reason, and the public interest has exactly zero to do with it.